[theora-dev] variable frame rate for Theora

Pablo Rodríguez oinos at web.de
Thu Nov 13 11:35:34 PST 2008

Thanks for the answer, Ralph.

Ralph Giles wrote:
> On Tue, Nov 11, 2008 at 11:45 AM, Pablo Rodríguez <oinos at web.de> wrote:
>> [...]. But I'd ask you to consider implementing
>> variable frame rates.
>> The reason for that implementation would come from the much smaller size
>>  in screencasts and presentations.
> We don't have any plans to add variable framerates to theora.
> There is a work around. Duplicating the previous frame is relatively
> cheap, so an encoder could set something like 5 fps, but only update
> the image when there's a change. The current encoder isn't smart
> enough to do this automatically, but a screencast app could force it.

Thanks for the workaround. What would it happen if the fps are set to 10 
or higher (100 or even 1000)?

> The other point is that theora isn't the best format for most
> presentations. I'd like to store them as an image stream, which can be
> variable framerate, or use a queue track like cmml to trigger slide
> advance in an adjacent viewer that holds the whole presentation. For
> presentations and screencasts with a lot of motion or animation video
> makes sense though.

As I wrote on my previous message, I'm not a programmer and I'm not sure 
I understand the previous paragraph.

Sure SWF, PDF or Moonlight would be better for presentations. But in 
some cases presentations should be delivered as movies (Blip.tv, Youtube).

> Are you working on anything with screencasts and theora?

No, I'm very interested in converting PDF presentations to movies with 
audio and synced slides (I have already done it with SWF, but I'd like 
to convert it to a movie using free codecs).

How can I get that? (I have the audio, PDF document and slide sync times)

Thanks for your help,


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